Looking for info on LRT tracks, where at a pinch point it goes from a double track to a shared single track and then back. New LRT under development in St. Louis Park - Minneapolis MN. Any locations that do this? Thanks
Hielsie
Ours doesn't.
With trains running every 7 1/2 minutes in each direction during rush hour we have an opposite direction meet about every 3 minutes. Putting them in opposite directions on one track, even for a short distance, would seem to be begging for trouble.
I bet the insurance company would resist it, too.
Dave
Lackawanna Route of the Phoebe Snow
According to one blog, single tracking is used a lot in Europe, and will be used in Vancouver, BC even.
http://railforthevalley.wordpress.com/2009/05/
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from the cold outpost of Edmonton, Alberta
In Los Angeles' Metro Rail system, the Metro Blue Line LRT runs double track from Downtown L.A. to Long Beach, over 20 miles away, where it runs in a single-track loop in the Long Beach downtown area, which becomes double-track upon return.
This is exactly the situation at the Ballpark interlocking (just timetable north/compass west of the Target Field station) of the existing Hiawatha LRT line in Minneapolis. The sidewalk along 5th St. runs right near by, so you can walk up and get a great view of it from public property. Apparently there was a building in the way so a pair of turnouts were installed with points facing each other. Trains scoot around the building but stop in one of two tail tracks where they set up for the return trip south to the Mall of America. Yes, its a very busy place...the 91 and 93 switches get quite a workout during rush hour! I was there for their installation and testing. Where the bumping posts are now near the incinerator I'm told is where the Southwest Service will begin and head out toward Eden Prairie. My guess is before that happens the track (or errant building!) will be "adjusted" so as to accommodate two tracks like the rest of the line.
This isn't all that uncommon. Back in the day when I was a signal & communications supervisor for one of the Class I's, there was a similar track arrangement at one of the busiest junctions on the division. Oh, yeah, it was a major choke point. It was dynamited and replaced with a universal crossover during my tenure.
MJE
There used to be a rail line from Ontario to Upland CA that was a single line most of the way. It went up a straight hill (Euclid Avenue) to Upland and back to Ontario on the same track. There were passing sidings with spring switches along the way (I don't know how many, maybe only one) and the downhill cars had the right of way. The uphill cars waited at the siding(s) until the downhill cars went by and then resumed the trip.
Oh, one other detail: the cars were mule-drawn and the mule rode in a special stall on the downhill trip.
Jack
Seriously now. The Sprinter light rail system from Oceanside CA to Escondido basically operates as a single track with a few extra long sidings where passing occurs. Sometimes this is at stations, but, if I recall correctly, not at all the stations. I believe that scheduling is rather rigid to ensure that passing happens where intended.
Unless it's been reconstructed, San Diego's LR system has a line that goes from double to single track for some distance to its end station. Development near that stretch is fairly built up, so it would be difficult to double track it now. Service is scheduled accordingly.
Germany has a variation on light rail double vs. single track. Near end stations where double-ended LRVs reverse direction, some double track lines use two "Y" turnouts to go to single track for a few meters, then back to double track into the station. This allows an arriving car or train to take either station track, as available. It's an economical alternative to using a scissors crossover with double track, if scheduling makes it practical.
In my other post I forgot two "backyard" examples. Pittsburgh's light rail system has two, short single-track stretches. One is active, the other not.
The active one, about 0.2 mi. long, carries the Brown Line (ex-52 Allentown) from the end of its double track at the intersection of Arlington Ave. and McCardle down a curving ramp to the Panhandle Bridge. There, it rejoins the double track line coming from the transit tunnel and Station Square and heading into downtown. This pinch point works because the Brown Line sees only one car per hour each direction in weekday rush hours. The far busier Red (ex-42) and Blue (ex-47) lines use the more direct Mt. Washington transit tunnel. The Brown Line, which runs from South Hills Jct. (south end of the tunnel) to downtown via Warrington and Arlington Aves. and the bridge, is also used as a detour by the Red and Blue Lines when the transit tunnel is out of service. At such times the pinch point on the bridge ramp demands some sharp dispatching.
The inactive stretch, about 0.4 miles long, runs from the subway junction at downtown's Steel Plaza to Penn Park at the Amtrak station and East Busway. Plans were to upgrade the spur as part of the light rail's North Shore Connector project, now pushing toward completion, but that fell through for lack of funding. It would have shuttled riders between Steel Plaza and the convention center. Instead, this stretch keeps its distinction as the first on a modern-era US light rail system to be abandoned. Track and signaling are still in place, though, so maybe some day...
Over here in South London (UK) the local Tram service has a number of single track sections. Even better the unofficial website has accurate track diagrams showing the transition from double to single track. One can be found at http://www.croydon-tramlink.co.uk/info/infra/diag.php?num=4. There are a number of others, including gauntletted track at Mitcham.
There are three examples of single track on the former Red Arrow LRT lines in the Philadelphia suburbs. The Norristown high speed line has bi-directional single track between the Bridgeport and Norristown stations because of a monumental, single track bridge between the two stations. The Media line has two long segments of bi-directional single track, one at the far end of the line in a Media street and another in the vicinity of the Spring Hill Shopping Mall (at least, I think that's the name), which goes through a very picturesque wooded area reminiscent of an old interurban line. The Sharon Hills line has a little over a mile of bi-directional single track at its end point.
Other posts mention the LA Blue Line and the San Diego system as examples of single track. The LA Blue Line does have single track at the Long Beach end, but it's a loop that is normally operated only in one direction (it's capable of operating bi-directionally, and did during some recent construction, but isn't normally run this way). The San Diego segment is at the far end of the Green Line at Santee, and is bi-directional.
Only one of these segments is a bi-directional single track segment between double track segments - the Media (PA) line segment near the Spring Hill Shopping Mall. The others are all "end of the line" segments.
Captain Correction to the rescue.
That's Springfield Shopping Center, not Spring Hill, and there's only 1 Sharon Hill, not Sharon Hills.
NJT's Camden to Trenton diesel Riverline is mostly single track. During 15 minute headways, which are weekday peak periods, there's a meet between north and southbound LRV's at every single track pinch point. Off peak is 30 minute service, so a meet at every other single track pinch point.
The last time I rode, probably about 10 years ago, Baltimore's Light rail line had several single track sections to which they were adding a fair amount of double track. I'm pretty sure the outer ends at BWI Airport, Penn Station and Hunt Valley still have single track.
Patrick Boylan
Free yacht rides, 27' sailboat, zip code 19114 Delaware River, get great Delair bridge photos from the river. Send me a private message
The River Line from Camden to Trenton NJ is mostly single track with some double track sections. Typical headway is 30 minutes but about 1/2 that during rush hours. Most meets occur at stations.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
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